1. Field of the Invention
The present invention relates in general to the field of storing information on optical medium, and more particularly to a method and system for reconditioning optical media to write updated information.
2. Description of the Related Art
As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.
Information handling systems often run applications that produce large quantities of data. One option available for storing large quantities of data on high capacity removable media is writing the data to optical disks such as compact disks (CDs) or digital versatile disks (DVDs). Re-writable optical disks, such as DVD+RW and CD-RW disks, offer the flexibility of re-using optical medium that has already had information stored on it. Re-writable optical medium have greater storage capabilities than magnetic floppy medium, and are adoptable to have similar functionality such as the embedding defect management and random writable file system capabilities through optical disk drives. Re-writable optical disk drives burn data onto re-writable disks with lasers that alter the characteristics of the disk. However, after a number of data writes, optical disk medium wear-out and are no longer able to accept data writes. A typical optical medium life expectancy is for 1000 re-writes before failure of the optical medium is expected.
One difficulty with re-writable optical medium is that re-writes are not typically distributed evenly across the entire disk so that some portions of a disk fail before other portions. For instance, in a Universal Disk Format (UDF) formatted random re-writable optical medium users often perceive a shortened life expectancy when certain disk areas, such as file system structures, experience a greater number of writes than other disk areas. As an example, the Universal Disk Format (UDF) specification defines file system structures such as the logical volume descriptor blocks, sparing tables for defect management and logical volume integrity descriptor blocks, to reside in the same logical block addresses. These file system structure areas are updated with each data write, resulting in a greater frequency of re-writes to the file system structure areas compared with data storage areas of the optical medium. The greater number of re-writes to the file system structure area leads to optical medium failure even though data storage areas, which have not experienced as frequent a number of re-writes, are able to support additional re-writes. In addition, repeated re-writes of the same information to a selected area of the optical medium can make the area unusable after just a few writes. For instance, repeated writing of a data point in the same position, as often occurs when a file structure is updated, alters the physical characteristics of the optical medium at the data point so that subsequent writes are ineffective. Even where the value of the data point changes with different writes, the repeated use of the same location often leads rapidly to an unusable medium at that location due to changing physical characteristics of the optical medium across the data point location, such as from varying melt and anneal conditions at the border of a data point location compared with the inner portion of the data point location.